X-Fingers replace lost digits, empower patients with new function

SolidWorks has helped make replacement fingers a reality.

The question, "Hey, Grandpa, where’d your fingers go?" haunted the man featured in the YouTube video for months after he lost two digits to a table saw. But somehow, he’s on the screen wiggling four normal-length fingers. Two he was born with; the other two Dan Didrick gave him. The latter are surgical steel digits called X-Fingers, which move, flex, and grasp just like his originals.

Didrick, of Naples, Fla., designed these, the world's first active-function artificial finger assemblies specifically for amputees, in SolidWorks software. He accomplished this feat over a two-week period with no engineering experience – just a week of self-paced tutorials. In fact, he didn’t know what computer-aided design was before he started using it. He’d whittled his first concept prototype from pine.

Eight years and 80-plus designs later, X-Fingers and X-Thumbs mimic natural body parts without any electronics. The criss-crossing surgical steel levers, which put the "X" in X-Fingers, are actuated by the remaining finger or thumb and covered in thermoplastic for a lifelike look and feel. Patients can pick up coins, button shirts, tie shoes, type letters, carry buckets – even play the piano.

X-Fingers, notes Didrick, are a huge leap from the traditional flaccid latex appendages whose only function is masking the problem. As such, X-Fingers have earned his company, Didrick Medical, global recognition:

X-Finger has been showcased in the Isimbardi Palace in Milan, Italy, as well as several museums, including the United States Patent and Trademark Museum, the California Science Center in Los Angeles, the Museum of Science and Industry in Chicago, the Museum of Science in Boston, the Vanderbilt Hall in Grand Central Terminal in New York City, and the National Inventors Hall of Fame.

X-Finger was a finalist in the 2009 INDEX: Awards in Copenhagen sponsored by the Crown Prince of Denmark and recognizing "designs for a better life."

An estimated 94 percent of all non-fatal amputations involve fingers, according to the US Bureau of Labor Statistics. Approximately 30,000 people are rushed to US emergency rooms each year because they've amputated one or more, often in a door slam or via power tools, according to the National Center for Injury Prevention and Control.

Hundreds of adult X-Fingers are in use today. Just entering volume production, they come in 500 different configurations covering five different finger thicknesses, 16 different lengths, and myriad injury profiles. Didrick makes these to order using electric discharge machining (EDM) driven by SolidWorks files. "When a patient needs X-Fingers, I pick a drawing, save it as STL or IGES, send it to a manufacturer, and it comes back a beautiful part," Didrick says. "SolidWorks is one of the most amazing tools I’ve ever used."

Years of hard work invested

It’s been a long road for the former medical equipment salesman who has taught himself engineering, patent basics, regulatory relations, manufacturing, and marketing. FDA approval was challenging enough; European approval was excruciating. Applying for the patents alone took a year. "It’s been difficult, but this is my life’s work," he says. "I do this 80 hours a week. I put everything into this."

One thing that came remarkably easy, however, was becoming productive with SolidWorks software. "SolidWorks has been really important," Didrick says. "I had the vision in my head and needed a way to make it reality.

SolidWorks helped me do exactly that in three weeks. Because of the complexity of the product and of the dynamics of the injured hand, I’ve been unable to find engineers who can help me. So it’s me and SolidWorks. Without SolidWorks, this never could have happened."

SolidWorks 3D CAD Software is available in Australia and New Zealand from Intercad Pty Ltd.